Ice cover waxed and waned.

The extra amount that disappeared last fall was equivalent to this much. It comes back in the winter, but not as permanent ice, as thin ice vulnerable. The amount remaining could be completely gone in summer in as little as five years.

There's no ice over it.

If its ice sheet melted completely, sea levels would rise by seven meters meaning that we cannot afford to lose even a small fraction of the ice sheet. Meanwhile, satellite data show that Antarctica s ice sheet, which is ten times larger than Greenland s, is losing ice as well.

Ice sheets would continue to disintegrate for centuries.

Last month, an unprecedented new low was reached after decades of decline. Indeed, the ice cap s area has decreased by half since the 1980 s, when summer sea ice still extended over roughly seven million square kilometers, as opposed to less than four million today.

So, there goes the ice caps, and there comes 240 feet of sea level rise.

Ice overlying the lake is 3,750 to 4,350 metres thick.

So what was going on here? We weren't covered in ice in Africa.

And there's a volcano behind, which has glaciers at the very top.

In the last three decades, its volume has shrunk by roughly three quarters. As the University of Laval s Louis Fortier puts it, we are three quarters of the way to ice free summers in the Arctic Ocean.

A topographic survey was carried out around the summit of Dome A, including the drilling of a 108 metre ice core.

Nobody imagined that the West Antarctic Ice Sheet was this dynamic.

But one area which is particularly intriguing for us is the northern region, you know, of Mars, close to the North Pole, because we see ice caps, and we see the ice caps shrinking and expanding, so it's very much like you have in northern Canada.

In addition to the sea ice loss, satellite data show that Greenland s three kilometer thick continental ice sheet is also melting at a record rate. In July, 97 of the sheet s surface was affected.

And I like this one, Snow Has Returned to Kilimanjaro.

Although West Antarctica s fate is sealed, we may still be able to prevent the collapse of East Antarctica s marine ice sheet. That means deciding sooner rather than later which path to follow.

We're working in most of the major glaciated regions of the northern hemisphere.

When there is more sunlight at high latitudes in summer, ice sheets melt.

They became marine. We now know them today from the ice caps.

Melting polar icecaps could also contribute to an increase in sea levels.

Most of Britain, all of Scandinavia, covered by ice several kilometers thick.

Particularly Mars, but also Europa, the small, icy moon around Jupiter.

I thought I would start with the logo. What's missing here, of course, is the North Polar ice cap.

The amount that disappeared in 2005 was equivalent to everything east of the Mississippi.

In the two years before my swim, 23 percent of the arctic sea ice cover just melted away.

Not simply to the flanks of the mountains, but to the very iced peaks which are the destiny of the pilgrims.

So many of us are convinced now that West Antarctica, the West Antarctic Ice Sheet, is starting to melt.

The system suddenly, very surprisingly, loses 30 to 40 percent of its summer ice cover.

So what that means is, what it tells us is that the Ross Sea region, this ice shelf, melted back and formed anew about 35 times.

Shrinking ice sheets make the planet darker, so it absorbs more sunlight and becomes warmer.

Greenland remains. Twenty eight years ago, this is what the polar ice cap the North Polar ice cap looked like at the end of the summer, at the fall equinox.

Even if the Arctic Ocean becomes ice free in the summer, most of the year it is not, and icebergs from melting glaciers will become more common and possibly larger. This, together with frequent, powerful, and icy storms that appear on short notice, increases the likelihood of blowouts and other spills.

And we saw about 35 alternations between open water and ice covered water, between gravels and these plant sediments.

The latest IPCC report describes our current predicament with disturbing clarity global temperatures are climbing, mountain glaciers and polar ice caps are melting, sea levels are rising, and extreme weather events are becoming more frequent and more severe.

A relatively small amount of melting beneath the Amundsen Sea s ice shelf has pushed its grounding line to the top of a sub glacial hill, from which it is now rolling down. Simply put, one thermal kick was enough to initiate an internal dynamic that will now continue under its own momentum, regardless of any action that humans might take to prevent it.

Meanwhile, global temperatures in recent months have been at their highest levels in records that go back 130 years. Arctic sea ice cover reached its lowest recorded average level for the month of June ever.

Examples of other effects include diminishing freshwater supply in many regions, due to extended droughts and as a result of the melting of high altitude glaciers and the decrease in snow cover in mountain areas.

The vanishing Arctic sea ice also affects the atmosphere. Less ice reflects less sunlight, and more open ocean absorbs more heat, which is then released into the atmosphere, affecting wind and pressure patterns throughout the northern hemisphere.

This risk is no longer merely theoretical. For the first time, findings based on observations and computer simulations all point to the same conclusion the huge Amundsen Sea sector of West Antarctica has begun an irreversible ice discharge, and nothing can now halt the subsequent drainage of the entire basin.

The North Polar ice cap is the same size geographically doesn't look quite the same size but it is exactly the same size as the United States, minus an area roughly equal to the state of Arizona.

This ice loss, caused largely by human induced global warming, has far reaching environmental, geopolitical, and economic consequences.

Crossing miles and miles of sastrugi frozen ice snowdrifts that could be hip deep.

The second pressure on the planet is, of course the climate agenda the big issue where the policy interpretation of science is that it would be enough to stabilize greenhouse gases at 450 ppm to avoid average temperatures exceeding two degrees, to avoid the risk that we may be destabilizing the West Antarctic Ice Sheet, holding six meters level rising, the risk of destabilizing the Greenland Ice Sheet, holding another seven meters sea level rising.

The air surrounding Greenland and Antarctica has recently become warmer and more humid. Warm and humid air will increase melting of ice in low regions at the edges of the ice sheets while boosting snowfall over cold high regions in the interior.